To some degree, could the language be a matter of comparison, i.e., contrasting one thing against another rather than making what we [with our Western mindset] would consider an "absolute" statement? For example, when Jesus said hate your father, mother, etc... He was apparently saying that in comparison, in contrast to the love and devotion we are to have for him, the love toward our earthly family pales that much in comparison that the Greek [or Hebrew/Aramaic] described it as "hate".
I understand this particular verse to mean, our very character has changed. We no longer sin without remorse, planning it, continuing it, WITHOUT repentance/turning/a desire to please Him. Paul described it as continually doing wrong, but that was no longer his heart's desire, and that in fact, it was no longer him that did it, but the sin that dwelt in him! Rather than doing the sin he had previously wanted, he now did the sin he no longer wanted. The battle against the flesh. The unsaved have no battle against the flesh. The flesh has [up until now] "won" and is in control. The born again believer still struggles with sin, but now it is a struggle, not just a careless, non-repentant, "I don't care" attitude. It's the change of heart, motive, desire, that comes from the new birth. IMO, if someone says they're a believer, but the Holy Spirit isn't within, convicting, guiding to repentance and to continuing to seek obedience, although it's not for me to judge, generally I believe the scripture is saying then that person has yet to be spiritually re-born.
If any man is in Christ He is a new creature. Behold the old is passing away, and all things are BECOMING new.
God bless, James.